A nucleus contains 17 protons and 20 neutrons. A second nucleus contains 17 protons and 18 neutrons.
Which comparison is correct?
They are isotopes with mass numbers 20 and 18.
They are different elements with mass numbers 37 and 35.
They are isotopes with mass numbers 37 and 35.
They are different elements with mass numbers 20 and 18.
103 exam-style questions on Edexcel GCSE Physics 6.1 Atomic structure and isotopes, covering 6.1.1 Structure of the atom, 6.1.2 Isotopes: atomic and mass number, 6.1.3 Sub-atomic particles: masses and charges, and 6.1.4 Electron orbits and energy changes. Each one has a worked solution and a mark scheme showing where the marks go.